Rodot:
If you are still / were considering a big screen project, I'm working on a library for a 3.2" on a mega 2560
@pYro_65 : The mega 2560 has more flash, more ram (good for gaming), more pins (to connect a 16b parallel screen instead of SPI) and you can adress external ram (yeaaaaah). But it's very, very expensive compared to a atmega 328. That's why I chose to do a cheap gaming platform first (to practice PCB routing too), and maybe later, if I want more power, I'll move on ARM 80Mhz 32bit stuff (but it's very difficult to hand solder).
That's understandable, If you find an AVR you like my library is easily transposable to any 8 bit AVR with at least 2x 8-bit wide IO ports. With a little modification it can support non-parallel interfaces, a large amount of speed will be lost, but will still be optimal.
The 1284 for example, has 16k ram and is available in through hole. From maniacbugs site it appears it has 2 free ports and is less than half the price of the 2560.
Anyway I shouldn't advertise my library until I release it, I'm just keen to do some collaborative work. A game is the fundamental reason behind my need for a new graphics driver. So keep that in mind if you ever re-ignite your project.